急倾斜特厚煤层耦合致裂与破碎工艺研发及应用

Research and application of the coupled crack and crush technology for steeply dipping extra-thick coal seam

水压致裂(hydraulic fracturing,HF)与预爆破(pre-split-blasting,PSB)是有效致裂坚硬煤岩体和促进安全开采的技术手段。其存在压裂效果差、润湿周期长、致裂方向、大小与范围有限和易诱发灾害等。针对急倾斜特厚煤层破碎难题,通过理论分析、数值计算、模型实验和现场应用等方法,揭示弱碱性石灰水耦合致裂与破碎机制。基于声发射(Acoustic emission,AE)观测与裂隙光学捕获(Crack Activity Optical Acquiisitions,CAOA)技术方法,揭示了煤岩体裂隙萌生扩展与转异规律。对比分析表明,在煤岩体体积膨胀中产生明显侧向压力,显著促进煤岩体裂隙扩展演化,裂隙扩展速度呈现先增后降趋势。应用实践表明,顶煤破碎度、冒放性和回采率显著提高,开采环境明显改善,这对急倾斜煤层安全高效开采与环境安全具有科学与工程应用价值。

Hydraulic fracturing（ HF） and pre-split blasting are available methods for coal-rock fracturing,but they present inadequate fracturing effect,long period wet-ability,the limitations of fracturing orientation and magnitude and range,easily inducing calamity,etc. Aimed at the problem of steep coalrock fracturing and cracking,we applied theoretical analysis,numerical computation,model material experiment,acoustic emission（ AE） and crack activity optical acquisitions（ CAOA）,the alkalescent limewater-surfactant solutions were proposed as base-material with coal seam fracturing. The multi-element compositing mechanism on static fracturing and crack method indicated that regularity of the internal crack conceiving,extending and evolution of specimens during static fracturing and crack. The analysis results manifested that the lateral swelling pressure emerged obviously in the process of hardening and inflating,and enhanced the internal crack extensibility and evolution. The trend of crack extensibility speed was rising and then declining,these had scientific and engineering application value for steep coal seam safe and efficient mining.